Known in the art is a composition for preventing deposition of inorganic salts comprising aminomethylenephosphonic acids, for example nitrilotrimethylenephosphonic acid of the general formula: ##STR3## and surfactant additives, for example a compound of the general formula: EQU [(C.sub.12 H.sub.25).sub.2 --N--(CH.sub.3).sub.2 ].sup.+ [Cl].sup.-
(cf. U.S. Pat. No. 3,467,192 Cl. 166-279; 1968).
Also known is a composition for preventing deposition of inorganic salts incorporating a polyethylenepolyamine-N-methylenephosphonic acid of the general formula: ##STR4## wherein n=0 to 14, and polyacrylamide (cf. U.S. Pat. No. 3,483,925 Cl. 166-279; 1968).
Also known is a process for preventing deposition of inorganic salts which is based on the use of an aqueous solution of a phosphonomethylated derivative of 1,3-diaminopropanol-2 in the acidic form corresponding to the general formula: ##STR5## (cf. USSR Inventor's Certificate No. 789434, Int. Cl..sup.3 E 21 B 43/12; 1980).
However, these compositions for preventing scaling of inorganic salts are insufficiently effective against deposition of barium sulphate. Furthermore, the use of polyacrylamide causes certain difficulties in the preparation of working solutions of a required concentration. Thus, this necessitates the use of high-speed mixers with cutting blades which inevitably results in non-productive consumption of labour and power.
The prior art composition most resembling that of the present invention in the subject matter and result obtained is a composition for preventing deposition of inorganic salts which comprises a phosphonomethylated derivative of 1,3-diaminopropanol-2 in the acid form corresponding to the following general formula: ##STR6## wherein n=1 to 5, and 1,3-diaminopropanol-2 and/or a derivative of 1.3-diaminopropanol-2 of the general formula: ##STR7## wherein n=1 to 5, hydrochloric acid, an alkali metal chloride and water, the components being present in the composition in the following proportions, percent by weight:
______________________________________ phosphonomethylated derivative of 1.3-diamino- 5.0-20.0 propanol-2 in the acid form 1,3-diaminopropanol-2 and/or 5.0-7.0 1,3-diaminopropanol-2 derivative hydrochloric acid 3.0-30.0 alkali metal chloride 3.0-7.0 water the balance. ______________________________________
(cf. USSR Inventor's Certificate No. 834334, Int. Cl..sup.3 E 21 B 43/00; 1981).
This composition, however, is insufficiently effective against deposition of barium sulphate.
Thus, when the known composition for preventing deposition of inorganic salts according to the USSR Inventor's Certificate No. 834334 is used in the amount of 100 mg/1, at lower limits of concentrations of the composition components the protective effect against deposition of barium sulphate is only 8.9%, while at upper limits of concentrations of the components it is equal to 36.3%.